Optical technology has made significant contributions to the state-of-the-art for long distance communications, including high reliability, low interference, security benefits, and (most important) very high bandwidth. However, the technology has yet to be successfully exploited in the domain of tightly-coupled multicomputer systems. Previous efforts in this area have concentrated on replacing existing electrical communications links with an optical counterpart. We propose to redesign the multicomputer architecture from the group up. To successfully exploit the benefits of optical technology in a tightly-coupled system, the architectural design must reflect both the advantages of optics and the limitations of optics. This paper describes a class of such architectures.